Regensburg 2025 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 33: Poster Graphene: Electronic Structure and Excitations
O 33.17: Poster
Dienstag, 18. März 2025, 13:30–15:30, P3
Transport Properties of Epitaxial Graphene on 4H-SiC(0001) and 6H-SiC(0001) on the Local Scale — •Simeon Bode1, Benno Harling1, Teresa Tschirner2, Klaus Pierz2, and Martin Wenderoth1 — 1IV. Physikalisches Institut, Georg-August-Universität Göttingen — 2Physikalisch-Technische Bundesanstalt (PTB), Braunschweig
Recent experiments on epitaxial graphene on silicon carbide have shown that transport properties strongly depend on the surface termination of the SiC substrate. Here, we study the impact of the polytype of the substrate SiC on various local properties of Polymer Assisted Sublimation Grown (PASG) graphene. Recently, it has been shown that there are two different surface terminations present at 6H-SiC [1], whereas mainly one surface termination was observed on 4H-SiC. The structural properties are investigated by STM and AFM, whereas electronic properties are extracted from STS data. Local transport measurements using Scanning Tunneling Potentiometry (STP) on 6H-SiC reveal variations in the sheet resistance from terrace to terrace when changing the stacking sequence across a step. On the other hand, the local sheet resistances of neighbouring terraces are very similar if the step height is half of a SiC unit cell, i.e., having the same termination on both sides. PASG graphene on 4H-SiC predominantly exhibits steps of half the unit cell. First data on 4H-SiC indicates that also on this system the sheet resistance is only slightly varying across steps. This work was financially supported by the DFG through the FOR5242. [1] Sinterhauf et al., Nat Commun 11, 555, 2020
Keywords: proximity effect; Scanning Tunneling Potentiometry; Scanning Tunneling Spectroscopy; SiC; epitaxial Graphene